Hot gas compressor bypass using oil separator circuit

Abstract

Hot gas bypass of compressed fluid is accomplished using standard components of an oil separation circuit. In this method, an electronically controlled valve, which is selectively opened and closed for returning oil accumulated in the oil separator is also selectively opened when a determination is made that hot gas bypass is desired. This electronically controlled valve is placed in the oil separator return line. When the valve is opened, hot gas is bypassed from compressor outlet into compressor inlet through the oil separator.

What is claimed is: 
     
       1. A method of operating a refrigeration cycle comprising the steps of: (1) providing a compressor having a suction inlet for receiving a refrigerant to be compressed and an outlet for delivering a compressed refrigerant to a downstream destination, providing an oil separator communicating with said outlet, and being operable to separate oil from compressed refrigerant, and providing a return line from said oil separator back to said compressor to return a separated oil;   (2) providing a controllable valve for selectively blocking or allowing flow through said return line between said oil separator and said compressor, and   (3) allowing refrigerant flow through said oil separator back to said compressor when a determination is made that it would be desirable to bypass compressed refrigerant from said outlet back to said compressor.   
     
     
       2. A method as recited in claim 1, wherein a controller operates an electronically controlled valve on said return line to achieve the selected blocking or allowing of flow through said return line, and said electronically controlled valve being opened when said determination is made that bypass is desirable. 
     
     
       3. A refrigeration system comprising: a compressor having a refrigerant suction line and a refrigerant outlet and a compressor unit for compressing a refrigerant;   an oil separator communicating with said outlet, said oil separator being operable to separate oil from said refrigerant in said outlet;   an oil return line for returning oil from said oil separator to said compressor; and   a valve mounted on said oil return line, and a control for operating said valve, said control opening said valve when a determination is made that a bypass of refrigerant from said outlet to said compressor is desirable.   
     
     
       4. A system as recited in claim 3, wherein said valve is an electronically controlled valve. 
     
     
       5. A system as recited in claim 4, wherein said electronically controlled valve is a solenoid valve. 
     
     
       6. A system as recited in claim 3, wherein said compressor is a scroll compressor. 
     
     
       7. A system as recited in claim 3, wherein said system is part of a refrigeration transport system. 
     
     
       8. A refrigeration system comprising: a refrigerant transport system including a container to be cooled;   a compressor having a refrigerant suction line and a refrigerant outlet and a compressor unit for compressing a refrigerant;   an oil separator communicating with said compressor outlet, said oil separator being operable to separate oil from said refrigerant in said compressor outlet;   an oil return line for returning oil from said oil separator to said compressor; and   an electronically controlled valve mounted on said oil return line, and a control for operating said valve, said control opening said valve when a determination is made that a bypass of refrigerant from said outlet to said suction is desirable.   
     
     
       9. A refrigeration system as recited in claim 8, wherein said valve also opens to allow oil to flow from said oil separator to said compressor. 
     
     
       10. A refrigeration system as recited in claim 8, wherein said valve is mounted on said return line and in said oil separator.